There isn't anything called "squatter's rights." What most non-lawyers call squatter's rights is what the law calls adverse possession. Under adverse possession, if someone other than the true owner of the property uses the property without the true owner's permission in a manner as if he were the true owner, he may be able to claim ownership of that land after some period of time. In Washington state, that time period is 10 years. Washington has recently enacted changes to its adverse possession law, which you can read about here: 2011 adverse possession law change